24 VDC construction equipment can be problematic to boost if it won't start at remote site unless you have 2 batteries in your truck and even then you would disconnect them from the truck before wiring in series. Many portable welders produce 25 VDC for welding. Has anyone ever heard of directly connecting the welding leads to construction equipment and using it to charge/boost?
Yes I have done this on older equipment pre 1986 stuff. It worked fine on stuff such as a 631-d d-9g,d8k . But this was before all of the electronic engine controls on modern equipment today. I would not dare try this on this modern stuff. just my two cents
Thanks, would the welder have enough juice to directly boost, or did you need to charge the system for awhile before it would start?
Well, I'm going to step way out on a limb with this one. First of all, I have no idea about the 25V welder boost. I'm certain 25V DC is not a problem boosting a 24V system, one volt doesn't seem a big deal when your alternator puts out 26 - 28 volts while charging, I'm more concerned about the amps the welder would put into the batteries. Maybe someone else out there knows. Now to step out on a limb. I've worked for many years around contractors type equipment, which is 12V. I've worked more around heavy equipment for the last 2 1/2 years, which is 24V, and that would be in a shop/yard environment. I deal with my dead 24V machines with a monster garage booster I built with 4 group 31 batteries, that thing will make any dead beast come to life. But you guys out in the field don't have that luxury. This thread made a light bulb go off in my head, the limb I'm going to step on. A 24V system is generally (2) 12V batteries wired in series, making the master positive and master negative going to the starter 24V. Your typical support trucks are Ford/Chevy/Dodge F350/3500 series trucks, diesel engines, which have (2) 12V batteries wired in parallel making the master positive and master negative going to the starter 12V. Now, how do we boost a 24V system with this? Here's the limb, maybe someone's done this and can let us know. You need two sets of jumper cables. Connect one set from one battery of your truck to one battery on your machine. Connect the other jumper cable set from the other battery of your truck to the other battery of your machine. Be very mindful of connecting positive to positive and neg to neg with your jumper, very critical. Your saying, "but it's a 24V system." It's only 24V at the master positive and master negative. Don't believe me? Take a multitester and read the volts on one of the batteries on the machine, it will read 12V. Go to the other battery, check it. It will also read 12V. The 24V only happens in the final output of the batteries wired in series at the starter, where master positive and master negative meet. Now, this is in theory in my head sparked by this thread and the need to boost 24V machines in the field. I think it would work, maybe someone has done this and would let us know. There it is, let's noodle it out. I'm sure a lot of guys have dead machines right now, it's going to be 5 degrees here tomorrow morning.
Thanks would say a 225A bobcat have the juice to directly boost or would you need to charge the system for awhile before it would start?
ATCO, Interesting theory, I might sketch this out tommorrow, I need to see if you would end up with 24V back at the truck
I used to do this too, only with a larger capacity DC welder. Like the others, I wouldn't dare try it on a machine with a computer or any kind of modern electronics. No buzz boxes! But electric motor driven generators did a good job. I used to let them charge a couple of 8D's in the larger Cats on a low setting for a bit just to get the juice flowing and warm the batteries up a bit (take the vent caps off first), then had someone hit the starter and cranked up the power off the welder at the same time. Tricky deal though. Blown batteries, burnt out starters and ruined welders were common in those days. Generally used Lincoln 400's or big Millers. Never hook straight to a battery with this procedure though, they will blow nearly every time. Go direct to the starter, and hook the ground last on something well away from the positive clamp. Sparks and other thing fly like hell sometimes when ya do this. Dangerous you know. On winter days like are happening now in Northern Michigan, I used to watch the Iron Mountain city water works people thaw cast iron or copper water pipes that had frozen. Oops, there's another geyser they'd say! Actually, they has some fair success with it. Watching the cold weather in the Midwest now. Don't miss it for nothing. ps: just read ATCO's postings. Yes, if you have a double set of jumpers, you can do what he outlines with a truck that has two batteries, or two separate trucks, doesn't matter which. Works fine, and two trucks doing it places less stress on either alternator. this is something else I've done many times. Like always, do it proper and wear eye protection anytime you work around bloody batteries.
miller and possibly lincoln have a option for a battery charging setting on some of their welders that allow a controlled charging of 12VDC and 24VDC batteries. The only one i can find it on right now is the big blue airpak, but i remember more having it.
Ah! Modern technology. Yes I've heard of this feature, but have never actually seen it. Most likely it's expensive.
In the past I've used 12V motors to jump start a 24V CAT V-12, The V-12 was already warm though. The main concern here is the electronics as previously mentioned, any damage done and the warranty might be voided. The welder should supply the juice, I wouldn't leave it as continous charging for any length of time.
I've seen 651 and down jumped a bunch of times with Bobcats. Another trick is that usually on a 24 volt system one battery will be lower than the other. Find it with the multimeter and then jump 12 to just that battery. Unless both batteries are completely dead you will have enought to start. I have also been thinking about whether or not a CV machine set at 25 volts would work for starting. Any input?
Have used my Lincoln 250 portable to jump 6-12 and 24 lots of times. the book on it says it can be used to jump or charge batteries but is rather vague. Have learned over the years to adjust current to approx the am-per hrs of the battery. IE 100 amp hrs battery = 100 amps on welder. Use DC setting and reverse polarity so you can hook ground clamp to battery + or starter assuming it is negative ground and then use electrode holder to clamp away from battery like on frame or some good piece of metal. also try to clamp so current does not have to flow through bearings etc. Fried a couple of FM radios till we learned to unhook them not just shut them off. Don't know about new rigs with circuit boards etc but have used them on a lot of combines that have a lot of electronics and so far no trouble. Let it charge for a few seconds like 30 or so and then have somebody ready to unhook the clamp to the frame as soon as it starts. Kind of hairy but sure beats fooling around.
The only way to make this setup work is to remove the series jumper between the batteries on the 24V machine. Since the neg. of one battery is connected to the positive of the other battery (on the 24V machine), you would effectively short the positive and the negative together at your 12V truck. Remove the jumper, and you're effectively charging two 12V batteries in parallel. Keep the jumper in and you have a dead machine and a dead truck.
ATCO is sort of on the right track, but I have a simpler method that works, its called the John C method. I once managed to leave something on in my truck (24 volt) and flattened the batteries. The skid steer was on the back of the truck. I hooked the jump cables from the skid battery to the first battery in the truck. Then I set the skid to a fast idle and went back inside for a coffee.....gave it about 15 minutes and that was enough juice to crank the truck. I have done this a number of times on different equipment. As you are essentially only dealing in 12 volt there should be no problem. Make sure you get it right if the recipient or donor machine has 6 volt cells though. When I'm jump/boost starting I always let the vehicles charge for 5 or 10 minutes before trying to crank.
For ATCO's proposal you are quite correct (charging two 12 volt from 2 x 12 volt) However: (See my above post) If the recipient vehicle is 24 volt and you are charging from 12volt the jumper to the Neg of the second battery (on the 24V machine) can stay in place. Just connect the 12 volt supply to the first battery. You can't get 24 volt backwards to the donor vehicle, its DC. And this is the same if you are boosting in the opposite direction.
That's correct. Also, for anyone in a pinch, you can use TWO 12 volt souces (jump and charger, for instance) simultaneously - just connect each 12 volt to each independant side of the series 24, and start engine.
Right-o. You can definitely make it work as squizzy has laid it out. I would place the jumper on the weaker of the two batteries and try to bring that one up; usually I find that one battery is just fine while the other has a weak charge. Boost the weak one and you're good to go.
battery Hello it is very common to add 12volt radio wiring it too 1 12 volt battery on a 24 volt system this over time will cause that battery to go dead and the other battery to become overcharged especially if the radio is played when engine not running like over a lunch hr.same goes for 12 volt lights and such remember electricty takes the path of least resistance mainy years ago we would come accross this problem we manufactured a simple box that simply switched the electrical load from 1 battery to the other and this stopped the uneven voltage of battery John Deere had this problem on there first 24 volt system called a balance load system I hope I explained this as operators might add something as a small radio never thinking they will cause a big problem later thanks as per jump starting mainy methods will work I use too use a 12 volt starter pac on 1 battery and my service truck on the second battery I sure the small welder will work well to get unit going BIG D
Have boosted 24v by directly connecting at both positive terminals on the starter solenoids(a little tricky if the accessibilty is not good),then connecting ground.Had good sucess with this set-up.I was thinking of buying a 24v portable booster pack-has anyone tried one of these yet?
special tool, Your all over the point I'm trying to make. You've suggested; if you have a dead 24V machine (2/12V batteries in series), you can connect a 12V battery "charger" to each 12V battery on the 24V machine, connect to proper positive/negative terminals in respect to red and black clamps of charger, turn the chargers on, wait, and start machine. Your exactly right, I've done it before. My point is, pertaining to the previous discussions, if there was a "24V feedback here, it would fry a charger", it doesn't. We have discussed various methods of boosting 24V machines here, and all are good methods, I'm just working with the simple premise of John Doe contractor arriving at the site in his Chevy 3500 with a Duramx diesel to find his D4H is going "ugggh" because it's so cold. It's not dead batteries as much as it just needs some help. I'm trying to determine a fast way he can boost his machine, right now, using his Chevy truck with two batteries, without disconnecting anything or any cables. If we apply your working application of using two "12V chargers" to boost a 24V system, how is that any different from using two sets of jumper cables connected battery to machine battery, then other battery to other machine battery, with cables connected to proper positive and negative terminals? I knew this would be an interesting technical conversation. I'm more than willing to be wrong here. But if I'm right, John Doe contractor has a fast/easy way to start that D4H and get to work.
The problem is the two batteries in the truck have a common ground. As soon as you connect the positive to the dozer with both batteries in the truck you have 24 Volts at the truck and the diodes in your alternator will blow like a 1 amp fuse in a 100 amp draw. If you disconnect the ground on one of the batteries in the truck, and then jump to the dozer, you should be OK. But like I said in an earlier post, unless both batteries are completely dead, you really only need to jump one battery to get the thing started.
You're absolutely correct. Center tapping a 24V system to run a 12V accessory will kill one of the batteries over time, and eventually take the other one with it. The best way to run a 12V accessory on a 24V system is to use a 24V-12V converter. They're inexpensive, easy to install, and will prolong the life of your batteries.
The only time I have heard of using a welder to jumpstart a 24 volt machine is in a Caterpillar workshop manual - in the warnings section, telling you NOT to do it under any circumstances. I would never have thought of it myself, but thanks to Caterpillar, I have kept it in mind in case I ever need to do it. Normally, if there is no other 24 volt machine around, I would try to get some charge into each battery separately, or just jump the flat one, depending on the circumstance, as posted above. A 24 volt system is really good for starting a 12 volt machine that has a lazy starter motor.........................
I agree 100%, and while the thread is very intresting and thought provoking I would and have done this several times off a van. Oh yes :yup I learned this the hard way :Banghead
What about A CV machine. My vantage 500 has CC/CV. I run it around 24V for NR-232 so it would be a breeze to jump a machine at 24V it will even go as low as 14V to jump a 12V system. I have tried this ONCE and it worked awesome. don't know if i would do it a second time though.
I agree with Tom K I have never tried this, but i would suggest getting a Series Parallel solenoid switch, these were quite common on old Cummins powered trk.s - start on 24 run on 12- Of coarse your service trk. would have to have more than one bat. When I was a lil pup jump starting with welders was common practice by large const. co. as well as the armed forces. Doing this requires a knack that most of us do not have. People were hurt from exploding batt. and burning wiring- as well as a # of reg. destroyed